The present invention relates to a conveyor apparatus and a commodity inspecting equipment equipped with such conveyor apparatus.
A commodity inspecting equipment such as a weighing conveyor for, while articles are successively transported by a conveyor apparatus in a production line, measuring the weight thereof includes, for example, a conveyor apparatus of a type in which an endless flat belt or the like is trained as a transport belt between a pair of rollers supported by a frame. One of the roller is a drive roller to which a driving force from a drive source such as a motor for moving the transport belt, and as a belt for transmission of the driving force an endless belt or the like is trained between a pulley, mounted coaxially on the drive roller, and a pulley mounted on a drive shaft of the drive source.
The conveyor apparatus is coupled with a free end side of an elastic element so that it can serve as a load to a load cell as a load detector. A fixed end side of the elastic element is coupled with a fixed member such as a leg member, a fixed frame, a fixed bracket or the like. The load cell is generally accommodated within a housing so that it will not be affected by an external environment such as moisture, dusts and others.
A relation in position between the conveyor apparatus and the housing is such that since a space above the conveyor apparatus is required to be open wide in view of articles to be weighed being placed on the conveyor apparatus and since measurements would result in an error when foreign matter falls onto the conveyor apparatus, the conveyor apparatus is generally disposed immediately above the housing or in side by side fashion relative to the housing. Accordingly, hitherto, the housing has an opening defined on a top surface or a side surface, and a support member for the support of the conveyor apparatus is passed through the opening so as to extend outwardly from the top surface or side surface of the housing. One end side of the support member is connected with the free end side of the elastic element, whereas the other end side thereof extends upwardly or laterally towards the conveyor apparatus, and the opening through which the support member extends is closed by a diaphragm.
In the meantime, this type of the weighing conveyor is sometime used for transport and weighing of food materials and, in such case, a water component and/or dregs of the food materials may fall and/or scatter onto the housing to deposit on surfaces of the housing. However, if the top surface or side surface of the housing has the opening through which the support member extends and the diaphragm or the like, the dregs deposited thereon tend to easily accumulate, resulting in proliferation of unwanted bacteria to such an extent as to result in degradation of sanitary conditions and also to perforation in the diaphragm as a result of the dregs or the like having been bitten. Also, even where a cleaning work is regularly performed using a cleansing liquid or the like, a surface structure of the top surface or side surface of the housing is complicated, resulting in the cleaning capability of the opening, diaphragm and their surroundings being reduced.
As a technique capable of dealing with the foregoing problems, there is what is disclosed in the Japanese Laid-open Patent Publication No. 9-297051. This technique is such that while the load cell is accommodated within a housing, a member for connecting a fixed end portion of an elastic element to a fixed member external to the housing is passed from a lower surface of the housing to the outside. By so doing, neither the opening nor the diaphragm is positioned above the top surface or side surface of the housing, resulting in improvement in capability of being cleaned.
However, in the technique disclosed in the above mentioned publication, the fixed end portion of the elastic element is connected with the fixed member external to the housing and the free end portion is connected with the housing. Also, a support member is mounted on a surface of the housing and the conveyor apparatus is supported by the housing. Accordingly, in addition to the weight of the conveyor apparatus, the weight of the support member or the weight of a drive transmission mechanism, such as the drive motor, the drive transmitting belt and pulleys or the like, the weight of the housing is loaded on the load cell as a tare weight and, therefore, the tare weight tends to become heavy, accompanied by reduction in natural frequency of a measurement system of the weighing conveyor, which in turn results in lowering of the weighing accuracy.
Also, in this weighing conveyor, the drive shaft of the drive motor extend in a direction perpendicular to the direction in which the elastic element of the load cell displaces upon receipt of a load. For this reason, the direction in which a portion of the centrifugal force generated as a result of rotation of the drive shaft acts coincides with the above mentioned direction of displacement of the elastic element. Accordingly, there has been a problem in that a weight signal outputted from the load cell contains noises and, therefore, the weighing accuracy tends to be lowered.
On the other hand, since the load cell is downwardly loaded with a load of the articles by the effect of a gravitational force, the direction in which the elastic element displaces during a load detection lie in a direction up and down. In other words, hitherto, in this type of the weighing conveyor, a transport surface of the conveyor apparatus lies perpendicular to the direction of displacement of the elastic element and the longitudinal axis of the drive shaft of the drive source lie parallel to the transport surface of the conveyor apparatus.
In view of the foregoing, in the event that a centrifugal force is generated as a result of rotation of the drive shaft of the drive source, accompanied by the generation of vibration, a portion of the direction of the vibration induced by the centrifugal force acts also in a direction up and down. Since the up and down direction lie in the direction in which the elastic element of the load cell displaces during the load detection, a change in load brought about by the vibrations is detected by the load cell, with the consequence that the weight signal from the load cell contains noises, resulting in reduction of the weighing accuracy.
The more considerable the fluctuation of the drive shaft being driven, the more considerable the vibration brought about by the effect of the centrifugal force. In other words, in the event that the mass of the rotating element is in an unbalanced state with respect to the center of rotation thereof or the drive shaft fluctuate about the longitudinal axis thereof during rotation thereof, the noises tend to become paramount.
In order to alleviate the above discussed problems, a technique disclosed in, for example, the Japanese Laid-open Patent Publication No. 8-136330 may be employed. In other words, in addition to a first standard load cell displaceable up and down to detect the weight of an article to be weighed, a second load cell is used and operable to displace in a horizontal direction parallel to a direction of transport. This second load cell is used to detect a vibration acting in the transport direction as a result of rotation of a rotary element. Since the vibration generated therein is a centrifugal force, it has an equal magnitude in all directions within a plane perpendicular to a plane of transport. Accordingly, by subtracting the vibration detected by the second load cell from a weight signal detected by the first load cell after the phase relationship between them has been rectified, noises resulting from the vibration can be eliminated.
However, with the known technique, plural load cells are required and, accordingly, not only does a hardware aspect become complicated, but also a software aspect of a signal processing for processing the weight signal becomes complicated, resulting in disadvantages in terms of cost. In view of this, there is a need to simplify the structure enough to avoid reduction in weighing accuracy which would otherwise results from containment of noises in the weight signal outputted from a load detector as a result of a rotatory vibration of the drive source.
Also, in this type of weighing conveyor, since the load cell, the drive motor and the drive transmission mechanism are all disposed between upper and lower runs of the transport belt, the conveyor apparatus tends to have an increased size particularly a heightwise direction thereof. Accordingly, since the natural frequency of the weighing conveyor decreases as a result of increase of the weight of the conveyor apparatus, that is, the tare weight, a low pass filter having a high cutoff frequency, for example, cannot be used. For this reason, the response of the filter does not increase so much and a filter processing time does not decrease so much, and accordingly, a high speed weighing operation is hampered.
Accordingly, the present invention has been devised in view of the foregoing problems and is intended to increase the accuracy of inspection including the weighing accuracy. Hereinafter, the present invention will be described in detail, including the underlying problems.
In order to alleviate the foregoing problems, an inspecting machine according to a first aspect of the present invention is a weighing conveyor characterized in that it includes a conveyor apparatus for successively transporting articles to be weighed, a load detector for detecting a weight of the articles to be weighed that are successively transported by the conveyor apparatus, and a housing for accommodating the load detector, wherein a fixed end of the load detector is connected with the housing and a free end thereof is connected with a support member for supporting the conveyor apparatus, said support member protruding outwardly from a bottom surface of the housing.
According to the first aspect, since the support member for connecting the load detector, accommodated within the housing, and the conveyor apparatus together is so configured as to protrude outwardly from the bottom surface of the housing, neither from a top surface of the housing nor from a side surface thereof, there is no need to provide an opening and a diaphragm in the top or side surface of the housing for passage of the support member therethrough.
Also, since it is not the structure in which the support member is provided in the housing and the conveyor apparatus is supported by the housing, there is no need to assembly various members on a surface of the housing. Accordingly, the housing can have a surface neat in finish and with neither projection nor indentation and, therefore, any possible deposition, stay and biting of the dregs of the article to be weighted can be suppressed. Also, a cleaning work is easy to perform, resulting in increase of a cleaning capability.
Also, since the housing is connected with the fixed end of the elastic element, no weight of the housing will be added to a tare weight and the tare weight does not therefore increase, resulting in increase of the weighing accuracy.
In a preferred embodiment of the above described first aspect, the conveyor apparatus is arranged immediately above the housing and the supporting member after having protruded outwardly from the bottom surface of the housing extends upwardly of the housing towards the conveyor apparatus.
According to this embodiment, by causing the support member once extending downwardly from the housing is bent so as to extend upwardly, the conveyor apparatus can be disposed immediately above the housing as usual. As a result thereof, a space above the conveyor apparatus is left wide open and the possibility of foreign matter falling from the housing onto the conveyor apparatus is avoided and, as a result, the increase of the weighing accuracy can be expected.
In another preferred embodiment of the above described first aspect, a surface of the housing confronting the conveyor apparatus is defined by a downwardly continuously inclined face.
According to this embodiment, even though dregs and others of the article to be weighed that is transported by the conveyor apparatus falls or scatter and then deposit on a surface of the housing, they will slip downwardly without being stayed or stagnated. Accordingly, inconveniences such as degradation of the sanitary condition and/or proliferation of unwanted bacteria can advantageously be avoided.
In a further preferred embodiment of the above described first aspect, a drive source for driving the conveyor apparatus is accommodated within the housing.
According to this embodiment, since arrangement has been made that the drive source such as a motor for driving the conveyor apparatus is also accommodated within the housing, no separate second housing for accommodating the drive source is needed. Accordingly, the structure of the weighing conveyor as a whole can be simplified and this contributes to alleviation of the problem associated with deposition of the dregs and the cleaning capability.
Also, since electric lines or the like for the drive source do not expose themselves to the outside of the housing, this renders a surface shape to be neat and the problem associated with deposition of the dregs and the cleaning capability can be alleviated. In addition, the electric lines or the like need not be passed through the diaphragm to the outside and inside of the housing and, therefore, degradation of the water proof feature and the dust proof feature can be avoided.
In a still further preferred embodiment of the above described first aspect, a drive transmission mechanism for transmitting a driving force of the drive source to the conveyor apparatus is accommodated within the support member.
According to this embodiment, arrangement has been made that by the utilization of the support member the drive transmission mechanism such as the drive transmission belt and pulleys are accommodated therein, a possible deposition of the dregs on the drive transmission mechanism can be prevented. Also, no separate housing for accommodating the drive transmission mechanism need be prepared and the weighing conveyor as a whole can therefore be simplified, thereby lessening the problem associated with the deposition of the dregs and the cleaning capability.
A conveyor apparatus according to a second aspect of the present invention is characterized in that when a frame structure is bent, an endless transport belt can be mounted on or removed from at least one pair of rollers supported by the frame structure, wherein a bending fulcrum of the frame structure lies at a location on one side of a line of extension, connecting respective axes of rotation of the rollers together when the frame structure is not bent, adjacent one of runs of the transport belt, and wherein there is provided a stop member for inhibiting the frame structure from being bent towards the other of the runs of the transport belt.
According to this second aspect, since when the frame structure is not bent, the bending fulcrum of the frame structure does not lie on the line of extension connecting the respective axes of rotation of the rollers and lies on one side adjacent one of the belt runs, this frame structure when the frame structure is not bent is tended to necessarily bend towards the other of the belt runs under the influence of a resilient restoring force of the transport belt then held taut. At this time, bending of the frame structure towards the other of the belt runs is barred and, therefore, when this frame structure when not bent is maintained and locked in a condition in which it is not bent.
As a result thereof, no lock pins or the like such as dedicated to avoid bending of the frame structure need be prepared separately and the structure of the conveyor apparatus can be simplified, the number of the component parts used can be suppressed and the cleaning capability is increased, resulting in increase of the weighing accuracy. Also, when the transport belt is to be mounted and removed, there is no need to manipulate any lock pin or the like and bending and straightening of the frame structure are sufficient, thereby simplifying the mounting and removal of the transport belt.
In a preferred embodiment of the above described second aspect, the other of the runs of the transport belt is a transport surface for the articles to be weighed.
According to this embodiment, by the action of a reactive force of the gravity of the article being transported and a reactive force resulting from the tension of the transport belt, the frame structure tends to bend in a direction in which the bending thereof is barred. As a result thereof, any possible unlocking of the posture of the frame structure during the transport of the article can be avoided.
In another preferred embodiment of the above described second configuration, the rollers are rotatable to allow the other of the runs of the transport belt to be held under tension.
According to this embodiment, since the force with which the frame structure tends to bend towards the other of the runs of the belt becomes stronger, this leads to the firm maintenance and locking of the frame structure in the non-bending condition when the frame structure is not bent.
In a further referred embodiment of the above described second aspect, a biasing member is employed for biasing at least one of the rollers in a direction required for a distance between the rollers to increase.
According to this embodiment, since the transport belt is held assuredly under tension at all times, the resilient restoring force thereof can be secured and it is warranted that the frame structure is locked in the non-bending condition. Also, the tension of the belt and, hence, the resilient restoring force of the belt can be adjusted to variably adjust the force with which the frame structure tends to bend.
In a still further preferred embodiment of the above described second aspect, the transport belt is provided with indentations engageable with the rollers to regulate displacement in position in a direction widthwise thereof.
According to this embodiment, since any possible displacement in position in a widthwise direction of the transport belt can be regulated, a tortuous motion of the belt can be suppressed to allow the belt to be held stably under tension. As a result, the resilient restoring force of the transport belt can be secured and, therefore, this warrants the locking of the frame structure in the non-bending condition.
In a still further preferred embodiment of the above described second aspect, the frame structure is provided with roofing member for supporting the run of the transport belt from backside thereof and wherein the stop member is defined by the roofing members.
According to this embodiment, where the roofing members are employed for supporting the run of the transport belt from rear to prevent the transport belt from being slackened to thereby facilitate a smooth transport of the article, the stop member is concurrently served by the utilization of the roofing members and, therefore, not only can the structure be simplified, but also the number of the component parts needed can be suppressed.
It is to be noted that the roofing members are exclusively utilized to stabilize a posture of the article to be transported during the transport thereof. In the weighing conveyor, to allow the article to be transported past a sensor or the like serving as an inspecting means while the article is in a stabilized posture without being fallen down is important in realizing a stable and assured weighing operation of the weighing conveyor. In the weighing conveyor, it is because if the article (the article to be weighed) falls down on the transport conveyor during the transport thereof, a weighing error may occur. On the other hand, in the case of a foreign matter detecting system in which the article is transported by the conveyor apparatus the presence or absence of foreign matter such as metallic particles mixed into the article being transported is inspected magnetically or by the utilization of X rays, it will constitute an error in detection of the foreign matter.
A conveyor apparatus according to a third aspect of the present invention is of a type wherein when a frame structure is bent, an endless transport belt can be mounted on or removed from at least one pair of rollers supported by the frame structure, said conveyor apparatus comprising a drive source for driving one of the rollers; a pulley mounted on a drive shaft of the drive source; a pulley mounted coaxial with one of the rollers; an endless drive transmitting belt trained between and around the pulleys, wherein a bending fulcrum of the frame structure lies at a location on one side of a line of extension of respective axes of rotation of the pulleys, when the frame structure is not bent, adjacent one of runs of the drive transmitting belt; and a stop member for inhibiting the frame structure from being bent towards the other of the runs of the drive transmitting belt.
According to this third aspect, in place of or in combination with the resilient restoring force of the transport belt trained between and around the rollers, and under the influence of the resilient restoring force of the drive transmission belt for transmitting the drive of the drive motor to the drive roller, the frame structure tends to bend towards the other of the belt runs. Accordingly, so long as the frame structure is not bent the condition in which they do not bend is firmly maintained and is thus locked. Since the article to be weighed that is placed on the transport belt can accordingly be transported in a stable posture, the weighing accuracy can be increased.
Also, when the frame structure is bent, mounting and removal of the transport belt can be performed simultaneously with mounting and removal of the drive transmission belt, respectively.
An article inspecting machine according to a fourth aspect of the present invention is equipped with the conveyor apparatus according to the above described second aspect.
In a preferred embodiment of the above described fourth aspect, there is provided an engagement for supporting a conveyor apparatus when engaged with the conveyor apparatus, and wherein the conveyor apparatus and the engagement are engaged with each other when a frame structure of the conveyor apparatus is not bent, but are disengaged from each other when the frame structure of the conveyor apparatus is bent.
According to this embodiment, when the frame structure of the conveyor apparatus is extended to a straight shape, mounting of the transport belt onto the conveyor apparatus and mounting of the conveyor apparatus onto the inspecting machine can be performed simultaneously. Also, when the frame structure of the conveyor apparatus is bent, removal of the transport belt from the conveyor apparatus and removal of the conveyor apparatus from the inspecting machine can also be performed simultaneously.
As a result thereof, there is no need to use separately any fixture or the like dedicated for use in installing the conveyor apparatus onto the inspecting machine and, therefore, not only can the structure of the article inspecting machine be simplified, but also the number of component parts needed can be suppressed to facilitate cleaning and to suppress any reduction in weighing accuracy. Also, when the conveyor apparatus is to be removed, there is no need to manipulate any fixture or the like and selective straightening or bending of the frame structure of the conveyor apparatus is sufficient and, thus, the operation to remove the conveyor apparatus can be simplified. In other words, the maintenance and the cleaning capability can be considerably increased.
An inspecting machine according to a fifth aspect of the present invention is a weighing conveyor for weighing a weight of an article to be weighed while the article to be weighed is transported, which weighing conveyor is characterized by including a conveyor apparatus for transporting the article to be weighed and having a transport surface laid horizontally; a drive source for driving the conveyor apparatus, and a load detector for supporting the conveyor apparatus and the drive source and for detecting the weight of the article to be weighed that is supported and transported by the conveyor apparatus, in terms of up and down displacement thereof, an axis of rotation of the drive source being arranged parallel to a direction of such displacement.
In a preferred embodiment of the above described fifth aspect, the drive source is arranged on a free end of the load detector.
Also, in another preferred embodiment of the above described fifth aspect, a drive transmission mechanism for transmitting a driving force of the drive source to the conveyor apparatus is employed, whereby an axis of a rotatory drive force generated by the drive source is converted into a direction parallel to the transport surface by the drive transmission mechanism.
The weighing apparatus according to the present invention is characterized in that it is equipped with the weighing conveyor according to the above described fifth aspect. This weighing conveyor can be optimally used particularly as a weighing apparatus (a weight checker).
According to the above described fifth aspect, where the transport surface of the conveyor apparatus lie perpendicular to the direction of displacement of the load detector, the axis of rotation of the drive source is rendered to be parallel to the direction of displacement, not parallel to the transport surface. In other words, the drive source is so disposed that the axis of rotation of the drive source can lie parallel to the direction of displacement of the load detector.
By so designing, the direction in which the rotational vibration of the drive shaft of the drive source acts and the direction of displacement of the load detector lie perpendicular to each other without coinciding with each other. Accordingly, it is possible to prevent the load detector from detecting vibration noises and, therefore, no extra external noises will not appear in the weight signal, thereby increasing the weighing accuracy.
Also, since the drive source is merely disposed so that the drive shaft of the drive source can extend in a direction parallel to the direction of displacement of the load detector, the hardware structure will not be complicated. Also, the weight signal can be used by itself and, therefore, no software structure of a signal processing is not complicated as well. In addition, since the transport surface is disposed horizontally, as compared with the type in which, for example, a pair of transport surfaces are laid vertically in face-to-face relation with each other with the article to be weighed being transported while sandwiched between the transport surfaces, a diversity of articles to be weighed can be transported.
Also, as the drive source, which is a major source of drive noises and which is a heavy item is disposed adjacent the free end of the load detector, the center of gravity of the drive source approaches the center of moment of the load detector and, therefore, the influence which would be brought about by an external disturbing noises to the load detector can be reduced. Moreover, even though the drive source which is the source of the drive noises exists at the free end, the load detector would not adversely affected by the drive noises since the direction in which the vibration acts is different from the direction of detection of the load detector.
In addition, where the drive transmission mechanism for transmitting the drive force of the drive source to the conveyor apparatus is employed so that by this drive transmission mechanism the axis of rotational drive force generated by the drive source can be converted into a direction parallel to the transport surface, the drive force of the drive source can be assuredly transmitted to the conveyor apparatus while the direction in which the axis of the rotational drive force generated by the drive source is properly corrected by the drive transmission mechanism.
In other words, since the axis of rotation of the drive source is laid parallel to the direction of displacement of the load detector, the axis of the rotational drive force initially generated by the drive source and the transport surface of the conveyor apparatus lie perpendicular to each other and do not therefore coincide with each other. Accordingly, by converting the axis of the rotational drive force into the direction parallel to the transport surface of the conveyor apparatus by the utilization of the drive transmission mechanism that is disposed between the drive source and the conveyor apparatus, a smooth drive transmission can be realized. By employing such structure, it is possible to realize versatile transport.
An inspecting machine according to a sixth aspect of the present invention is a weighing conveyor for weighing a weight of an article to be weighed while the article to be weighed is transported, which weighing conveyor is characterized by including a conveyor apparatus for transporting the article to be weighed; a drive source for driving the conveyor apparatus; a drive transmitting mechanism for transmitting a drive force of the drive source to the conveyor apparatus; and a load detector for supporting the conveyor apparatus, the drive source and the drive transmitting mechanism and for detecting the weight of the article to be weighed that is supported and transported by the conveyor apparatus, wherein the conveyor apparatus is disposed above the load detector, the drive source is disposed at a location substantially level with the load detector, or below the load detector, with respect to an up and down direction, and the drive transmission mechanism is disposed so as to extend between a position below the load detector and a position above the load detector with the load detector intervening therebetween, such that a composite center of gravity of the conveyor apparatus, the drive source and the drive transmission mechanism is brought to a position in a vicinity of a center of moment of the load detector in the up and down direction.
An inspecting machine according to a seventh aspect of the present invention is a weighing conveyor for weighing a weight of an article to be weighed while the article to be weighed is transported as is the case with the sixth aspect, which weighing conveyor is characterized by including a conveyor apparatus for transporting the article to be weighed; a drive source for driving the conveyor apparatus; a drive transmitting mechanism for transmitting a drive force of the drive source to the conveyor apparatus; and a load detector for supporting the conveyor apparatus, the drive source and the drive transmitting mechanism and for detecting the weight of the article to be weighed that is supported and transported by the conveyor apparatus, wherein the conveyor apparatus is disposed below the load detector, the drive source is disposed at a location substantially level with the load detector with respect to an up and down direction, and the drive transmission mechanism is disposed so as to extend between a position below the load detector and a position above the load detector with the load detector intervening therebetween, such that a composite center of gravity of the conveyor apparatus, the drive source and the drive transmission mechanism is brought to a position in a vicinity of a center of moment of the load detector in the up and down direction.
An inspecting machine according to an eighth aspect of the present invention is a weighing conveyor for weighing a weight of an article to be weighed while the article to be weighed is transported as is the case with the sixth aspect, which weighing conveyor is characterized by including a conveyor apparatus for transporting the article to be weighed; a drive source for driving the conveyor apparatus; a drive transmitting mechanism for transmitting a drive force of the drive source to the conveyor apparatus; and a load detector for supporting the conveyor apparatus, the drive source and the drive transmitting mechanism and for detecting the weight of the article to be weighed that is supported and transported by the conveyor apparatus, wherein the load detector is arranged at a location substantially intermediate of the conveyor apparatus with respect to a direction of transport of the article to be weighed, the drive source is arranged adjacent the load detector and the drive transmission mechanism is arranged so as to extend between a position downstream of the direction of transport and a position upstream of the direction of transport with the load detector intervening therebetween, such that a composite center of gravity of the conveyor apparatus, the drive source and the drive transmission mechanism is brought to a position in a vicinity of a center of moment of the load detector in the transport direction.
An inspecting machine according to a ninth aspect of the present invention is a weighing conveyor for weighing a weight of an article to be weighed while the article to be weighed is transported as is the case with the sixth aspect, which weighing conveyor is characterized by including a conveyor apparatus for transporting the article to be weighed; a drive source for driving the conveyor apparatus; a drive transmitting mechanism for transmitting a drive force of the drive source to the conveyor apparatus; and a load detector for supporting the conveyor apparatus, the drive source and the drive transmitting mechanism and for detecting the weight of the article to be weighed that is supported and transported by the conveyor apparatus, wherein the load detector is arranged substantially intermediate of the conveyor apparatus with respect to a transport widthwise direction of the article to be weighed, the drive source is arranged at a location substantially level with the load detector with respect to the transport widthwise direction, and the drive transmission mechanism is arranged so as to extend between a position substantially level with the load detector and a position leftwards or rightwards of the transport widthwise direction, or so as to extend between respective positions leftwards and rightwards of the transport widthwise direction with the load detector intervening therebetween, such that a composite center of gravity of the conveyor apparatus, the drive source and the drive transmission mechanism is brought to a position in a vicinity of a center of moment of the load detector in the transport widthwise direction.
In a preferred embodiment of the sixth aspect, the load detector is arranged substantially intermediate of the conveyor apparatus with respect to the direction of transport of the article to be weighed, the drive source is positioned adjacent the load detector, and the drive transmission mechanism is arranged so as to extend between respective positions upstream and downstream of the direction of transport with the load detector intervening therebetween, such that the composite center of gravity of the conveyor apparatus, the drive source and the drive transmission mechanism is brought to the position in the vicinity of the center of moment of the load detector also in the direction of transport.
In another preferred embodiment of the sixth aspect, the load detector is arranged substantially intermediate of the conveyor apparatus with respect to the transport widthwise direction, the drive source is positioned at a location substantially level with the load detector with respect to the transport widthwise direction, and the drive transmission mechanism is arranged so as to extend between a location substantially level with the load detector with respect to the transport widthwise direction and a location leftward or rightward of the transport widthwise direction, or so as to extend between respective locations leftwards and rightwards of the transport widthwise direction with the load detector intervening therebetween, such that the composite center of gravity of the conveyor apparatus, the drive source and the drive transmission mechanism is brought to the position in the vicinity of the center of moment of the load detector also in the transport widthwise direction.
The weighing apparatus of the present invention is featured in that the weighing conveyor according to the sixth aspect is employed. This weighing conveyor is most suitably used particularly as a weighing apparatus (a weight checker).
In the weighing conveyor according to any one of the previously described sixth to ninth aspects, since arrangement of the conveyor apparatus, the drive source and the drive transmission mechanism relative to the load detector is comprehensively taken into consideration and the weights are uniformly balances, the center of gravity of the weighing conveyor is positioned in the vicinity of the center of moment of the load detector.
Accordingly, the center-to-center distance between the center of gravity of the conveyor apparatus and the center of moment of the load detector can be reduced to minimize the force of moment acting on the load detector. As a result thereof, the frequency region of the noise component to be removed can be increased to reduce the filter processing time and, therefore, a high speed weighing operation can be attained to thereby increase the weighing accuracy.
Also, particularly in the weighing conveyor according to the sixth aspect, when the drive transmission mechanism is to be disposed between the conveyor apparatus, positioned above the load detector, and the drive source positioned at a location substantially level with the load detector or below the load detector, and when the drive transmission mechanism is disposed so as to extend up and down with the load detector intervening therebetween, the weights in the up and down direction of the conveyor apparatus can be balanced and the center of gravity of the conveyor apparatus can be brought close to the center of moment of the load detector with respect to the up and down direction.
In the weighing conveyor according to the seventh aspect, when the drive transmission mechanism is to be disposed between the conveyor apparatus, positioned below the load detector and the drive source arranged at a location substantially level with the load detector, the drive transmission mechanism is so arranged as to extend up and down with the load detector intervening therebetween. Accordingly, the weights in the up and down direction of the conveyor apparatus are well balanced and the center of gravity of the conveyor apparatus can be brought close to the center of moment of the load detector with respect to the up and down direction.
Also, in the weighing conveyor according to the eighth aspect, when the drive transmission mechanism is to be disposed between the conveyor apparatus, which has been disposed with its weight balanced in the transport direction relative to the load detector, and the drive source arranged at a location close to the load detector, the drive transmission mechanism is so arranged as to extend in a direction parallel to the transport direction with the load detector intervening therebetween. Accordingly, the weights in the transport direction of the conveyor apparatus are well balanced and the center of gravity of the conveyor apparatus can be brought close to the center of moment of the load detector with respect to the transport direction.
Again, in the weighing conveyor according to the ninth aspect, when the drive transmission mechanism is to be disposed between the conveyor apparatus, which has been disposed with its weight balanced in the transport widthwise direction relative to the load detector, and the drive source arranged at a location substantially level with the load detector in the transport widthwise direction, the drive transmission mechanism is so arranged as to extend between the position substantially level with the load detector in the transport widthwise direction and the position either leftwards or rightwards thereof or as to extend in a direction parallel to the transport widthwise direction with the load detector intervening therebetween. Accordingly, the weights in the transport widthwise direction of the conveyor apparatus are well balanced and the center of gravity of the conveyor apparatus can be brought close to the center of moment of the load detector with respect to the transport widthwise direction.
Furthermore, in a preferred embodiment of the weighing conveyor according to the sixth aspect, the center of gravity of the conveyor apparatus is brought in the close vicinity of the center of moment of the load detector in two dimensions including the up and down direction and the transport direction. Hereinafter, the preferred embodiments of the present invention, including their underlying problems will be discussed in detail with reference to the accompanying drawings.